Centering mechanisms for a surgical access assembly

ABSTRACT

An access assembly includes an instrument valve housing defining a cavity, and a valve assembly. The valve assembly includes a flange seal member, a seal assembly, a centering mechanism, and a retainer frame assembly. The flange seal member includes an arcuate portion configured to adjustably engage first and second surfaces of the instrument valve housing in a sealing relation. The centering mechanism is configured to bias the valve assembly towards a generally centered position within the cavity. The centering mechanism includes a plurality of coils including inner coil portions operatively secured with the seal assembly, and outer coil portions configured to engage the first surface of the instrument valve housing. The retainer frame assembly includes first and second members. The inner coil portion of the centering mechanism is disposed between seal assembly and the second member of the retainer frame assembly.

FIELD

The present disclosure relates to surgical access assemblies forminimally invasive surgery. More particularly, the present disclosurerelates to centering mechanisms for use with the surgical accessassemblies.

BACKGROUND

In order to facilitate minimally invasive surgery, a working space mustbe created in the desired surgical space. An insufflation gas, typicallyCO₂, is introduced into the abdomen of the patient to create an inflatedstate called pneumoperitoneum. Surgical access assemblies are utilizedto allow the introduction of surgical instrumentation and endoscopes (orother visualization tools). These surgical access assemblies maintainthe pressure for the pneumoperitoneum, as they have one or more seals.Typically, a “zero-seal” in the surgical access assemblies seals asurgical access assembly in the absence of a surgical instrumenttherein, and an instrument seal seals around a surgical instrument thatis inserted through the surgical access assembly.

Surgical procedures require a robust seal capable of adjusting tomanipulation of surgical instrumentation extending through the surgicalaccess assemblies without compromising seal integrity. Therefore, itwould be beneficial to have a surgical access assembly with improvedseal capability and durability.

SUMMARY

In accordance with an embodiment of the present disclosure, an accessassembly includes an instrument valve housing defining a cavity, and avalve assembly disposed within the cavity of the instrument valvehousing. The valve assembly includes a flange seal member, a sealassembly, a centering mechanism, and a retainer frame assembly. Theflange seal member includes an arcuate portion configured to adjustablyengage first and second surfaces of the instrument valve housing in asealing relation. The seal assembly is configured to engage a surgicalinstrument inserted into the access assembly in a sealing relation. Thecentering mechanism is configured to bias the valve assembly towards agenerally centered position within the cavity of the instrument valvehousing. The centering mechanism includes a plurality of coils arrangedin a circular configuration and defines a central opening. The pluralityof coils includes inner coil portions operatively secured with the sealassembly, and outer coil portions configured to engage the first surfaceof the instrument valve housing. The retainer frame assembly isconfigured to couple the centering mechanism, the flange seal member,and the seal assembly as a single construct. The retainer frame assemblyincludes first and second members. The inner coil portion of thecentering mechanism is disposed between seal assembly and the secondmember of the retainer frame assembly.

In an embodiment, the centering mechanism may have a substantially flatprofile.

In another embodiment, the centering mechanism may be formed of aresilient material to transition the centering mechanism between a firststate, in which, the central opening of the centering mechanism isdisposed in a generally centered position, and a second state, in which,the central opening is radially displaced from the generally centeredposition.

In yet another embodiment, portions of the centering mechanism may becompressible when the centering mechanism is in the second state.

In an embodiment, each coil of the plurality of coils of the centeringmechanism may have a circular profile.

In another embodiment, each coil may extend between the first surface ofthe instrument valve housing and a gap defined by a pair of adjacentpins of the first member of the retainer frame assembly.

In yet another embodiment, adjacent inner coil portions may define a gaptherebetween.

In an embodiment, the first member of the retainer frame assembly mayinclude a plurality of pins, and the second member of the retainer frameassembly may define an annular groove configured to receive theplurality of pins.

In another embodiment, each pin of the plurality of pins of the firstmember may be at least partially disposed in the gap defined between theadjacent inner coil portions such that at least a portion of each innercoil portion is secured between adjacent pins.

In an embodiment, the outer coil portions of the centering mechanism maybe radially outward of the second member of the retainer frame assembly.

In another embodiment, the seal assembly may include a plurality ofradial protrusions peripherally arranged about a central opening of theseal assembly. Each radial protrusion of the plurality of radialprotrusions may be configured to support a corresponding inner coilportion of the centering mechanism.

In yet another embodiment, the valve assembly may further include aguard assembly configured to be secured with the flange seal member. Theguard assembly may be configured to protect the seal assembly duringinsertion and manipulation of a surgical instrument.

In still yet another embodiment, the flange seal member may includeopposing first and second surfaces. The guard assembly may be disposedon the first surface of the flange seal member in a superposed relation,and the seal assembly may be detachably secured with the second surfaceof the flange seal member.

In accordance with another embodiment of the present disclosure, anaccess assembly includes an instrument valve housing defining a cavity,and a valve assembly disposed within the cavity of the instrument valvehousing. The valve assembly includes a flange seal member, a sealassembly, and a centering mechanism. The flange seal member includes anarcuate portion configured to adjustably engage lateral and distalsurfaces of the instrument valve housing in a sealing relation. The sealassembly is configured to engage a surgical instrument inserted into theaccess assembly in a sealing relation. The centering mechanism isconfigured to bias the valve assembly towards a generally centeredposition within the cavity of the instrument valve housing. Thecentering mechanism includes a mesh having a toroidal shape. The mesh isconfigured to be interposed between the lateral surface of theinstrument valve housing and a portion of the flange seal member.

In an embodiment, the mesh may be disposed distally of the arcuateportion of the flange seal member.

In another embodiment, the mesh may be transitionable between a firststate, in which, a central opening defined by the mesh is in a generallycentered position, and a second state, in which, the central opening ofthe mesh is radially displaced.

In an embodiment, the valve assembly may include a retainer frameassembly including first and second members. The retainer frame assemblymay be configured to couple the flange mechanism, the flange sealmember, and the seal assembly as a single construct.

In another embodiment, the central opening of the mesh may beconcentrically disposed with a central opening defined by the sealassembly.

In an embodiment, a portion of the arcuate portion of the flange sealmember may be in superposed relation with the mesh.

In another embodiment, the mesh may be radially compressible such that aportion of the arcuate portion of the flange seal member engages thelateral surface of the instrument valve housing when at least a portionof the mesh is compressed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the disclosureand, together with a general description of the disclosure given above,and the detailed description of the embodiments given below, serve toexplain the principles of the disclosure, wherein:

FIG. 1 is a perspective view of a surgical access assembly in accordancewith an embodiment of the present disclosure;

FIG. 2 is a perspective view of an instrument valve housing of thesurgical access assembly of FIG. 1;

FIG. 3 is a bottom perspective view of the instrument valve housing ofFIG. 2;

FIG. 4. is a top perspective view of a valve assembly of the instrumentvalve housing of FIG. 2 in accordance with an embodiment of the presentdisclosure;

FIG. 5 is a bottom perspective view of the valve assembly of FIG. 4;

FIG. 6 is an exploded perspective view of the valve assembly of FIG. 4with parts separated;

FIG. 7 is a cross-sectional view of the surgical access assembly takenalong section line 7-7 of FIG. 1, illustrating the valve assembly in agenerally centered position;

FIG. 8 is a cross-sectional view of the surgical access assembly takenalong section line 7-7 of FIG. 1, illustrating the valve assembly in aradially displaced position;

FIG. 9 is a cross-sectional view of a surgical access assembly inaccordance with another embodiment of the present disclosure;

FIG. 10 is a cross-sectional view of the surgical access assembly ofFIG. 9, illustrating radial displacement of a valve assembly of FIG. 9;

FIG. 11 is a perspective view of a centering mechanism of a valveassembly for use with the surgical access assembly of FIG. 1 inaccordance with another embodiment of a present disclosure;

FIG. 12 is a perspective view of an instrument valve housing includingthe centering mechanism of FIG. 11 with portions of the housing removed;

FIG. 13 is a perspective view of a valve assembly of the instrumentvalve housing of FIG. 12;

FIG. 14 is a cross-sectional view of the valve housing of FIG. 12; and

FIG. 15 is a cross-sectional view of the valve housing of FIG. 14,illustrating radial displacement of the valve housing.

DETAILED DESCRIPTION

Particular embodiments of the present disclosure are describedhereinbelow with reference to the accompanying drawings; however, it isto be understood that the disclosed embodiments are merely exemplary ofthe specific disclosure and may be embodied in various forms. Well-knownfunctions or constructions are not described in detail to avoidobscuring the present disclosure in unnecessary detail. Therefore,structural and functional details disclosed herein are not to beinterpreted as limiting, but merely as a basis for the claims and as arepresentative basis for teaching one skilled in the art to variouslyemploy the present disclosure in virtually any appropriately detailedstructure. Like reference numerals refer to similar or identicalelements throughout the description of the figures.

As used herein, the term “distal” refers to that portion of theinstrument, or component thereof which is farther from the user whilethe term “proximal” refers to that portion of the instrument orcomponent thereof which is closer to the user. As used herein, the term“about” means that the numerical value is approximate and smallvariations would not significantly affect the practice of the disclosedembodiments.

With initial reference now to FIGS. 1-3, a surgical access assemblyaccording to aspects of the present disclosure is shown generally as acannula assembly 100. The cannula assembly 100 may be utilized duringminimally invasive surgery, e.g., laparoscopic surgery, and provide forthe sealed access of surgical instruments into an insufflated bodycavity, such as the abdominal cavity. The cannula assembly 100 includesa cannula 102 and an instrument valve housing 110 detachably secured tothe cannula 102. The instrument valve housing 110 defines a longitudinalpassage 111 for receipt of a surgical instrument 10. In addition, theinstrument valve housing 110 defines a cavity 115 configured toadjustably support a valve assembly 120 therein. The valve assembly 120is supported within the instrument valve housing 110 to provide sealedpassage of the surgical instrument 10 through the cannula assembly 100.In embodiments, the instrument valve housing 110 may include, e.g.,knurls, indentations, tabs, or be otherwise configured to facilitateengagement by a clinician.

The cannula assembly 100 may be configured for use with an obturator(not shown) inserted through the instrument valve housing 110 and thecannula 102. The obturator may have a blunt distal end, or a bladed ornon-bladed penetrating distal end. The obturator may be used to incisethe abdominal wall so that the cannula assembly 100 may be introducedinto the abdomen. The handle of the obturator may engage or selectivelylock into the instrument valve housing 110 of the cannula assembly 100.For a detailed description of the structure and function of exemplaryobturators and cannulas, reference may be made to commonly ownedInternational Patent Publication No. WO 2016/186905 (“the '905publication”), the entire disclosure of which is hereby incorporated byreference herein.

In addition, the cannula assembly 100 may also include features forsecurement with a patient. For example, a distal end of the cannula 102may support a balloon anchor or another expandable member that engagesthe abdomen from the interior side. A feature on the opposite side ofthe abdominal wall may be used to further stabilize the cannula assembly100, such as adhesive tabs or adjustable foam collars. For a detaileddescription of such features on a cannula assembly, reference may bemade to commonly owned U.S. Pat. No. 7,300,448 (“the '448 patent”), theentire disclosure of which is hereby incorporated by reference herein.

With reference now to FIGS. 4-6, the valve assembly 120 in accordancewith an embodiment of the present disclosure includes a flange sealmember 130, a guard assembly 140, a seal assembly 150, a centeringmechanism 160, and a retainer frame assembly 180. The flange seal member130 includes an annular base 132 and a flange portion 138 extending fromthe annular base 132 such that the flange seal member 130 defines arecess 135 configured to receive the guard assembly 140 therein. Theannular base 132 defines a central opening 132 a configured to receivethe surgical instrument 10 therethrough, and a plurality of bores 132 bcircumferentially defined about the central opening 132 a. The pluralityof bores 132 b is configured to receive respective pins 182 of a firstmember 181 of the retainer frame assembly 180, as will be discussedbelow.

In particular, the flange portion 138 of the flange seal member 130includes an arcuate portion 134 extending radially outward. The arcuateportion 134 includes inner and outer segments 134 a, 134 b defining agap (not shown) therebetween. Under such a configuration, the arcuateportion 134 is configured to adjustably engage a first surface such as,e.g., a distal surface (not shown), of the instrument valve housing 110in a sealing relation and maintain such contact during insertion andmovement of the surgical instrument 10 in the longitudinal passage 111(FIG. 2). For example, the distal surface of the instrument valvehousing 110 may be orthogonal to a longitudinal axis “L-L” (FIG. 2)defined by the longitudinal passage 111 of the instrument valve housing110. A conventional base seal member may suffer from buckling or bendingduring movement thereof, which may result in a loss of sealing contactwith the surgical instrument 10 and/or the instrument valve housing. Incontrast, the flange seal member 130 engages the instrument valvehousing 110 in a sealing relation during movement of the valve assembly120 within the cavity 115. In particular, the arcuate portion 134 of theflange seal member 130 adjustably engages the distal surface of theinstrument valve housing 110 to enable sealing contact during, e.g.,radial, movement in the cavity 115.

In addition, the arcuate portion 134 of the flange seal member 130 isconfigured to adjustably engage a second surface such as, e.g., alateral surface 110 a (FIG. 3), of the instrument valve housing 110 in asealing relation during an off-centered movement of the seal assembly120. The lateral surface 110 a may be substantially parallel to thelongitudinal axis “L-L” (FIG. 2) defined by the longitudinal passage 111(FIG. 2) of the instrument valve housing 110. Under such aconfiguration, the arcuate portion 134 may sealingly engage two surfacesthat are substantially orthogonal to each other. In particular, the gapdefined between the inner and outer segments 134 a, 134 b of the arcuateportion 134 of the flange seal member 130 enables the arcuate portion134 to adjustably engage the lateral surface 110 a, as well as thedistal surface (not shown), of the instrument valve housing 110 in asealing relation during movement of the valve assembly 120.Specifically, when a portion of the centering mechanism 160 iscompressed against the lateral surface 110 a of the instrument valvehousing 110, the outer segment 134 b of the arcuate portion 134 of theflange seal member 130 may deflect radially inward to maintain sealingcontact with the instrument valve housing 110. Under such aconfiguration, the flange seal member 130 may engage the instrumentvalve assembly 110 at multiple locations and enhance sealing relationwith the instrument valve assembly 110. In this manner, the flange sealmember 130 is configured to engage at least two surfaces of theinstrument valve housing 110 in a sealing relation when the centeringmechanism 160 is radially off-center, as will be discussed below.

With particular reference to FIG. 6, the guard assembly 140 isconfigured to be disposed in the recess 135 defined in the flange sealmember 130, in a superposed relation with the annular base 132. Theguard assembly 140 is configured to protect the seal assembly 150 duringinsertion and withdrawal of the surgical instrument 10 into and from theseal assembly 150. The guard assembly 140 includes an annular member 142and a plurality of petals 144 circumferentially supported on the annularmember 142 such that adjacent petals 144 are at least partiallyoverlapped to enable slidable movement therebetween. The plurality ofpetals 144 defines a central opening 146. The petals 144 also operate toguide and orient the surgical instrument 10 through the seal assembly150. The central opening 146 is configured for receipt of the surgicalinstrument 10 therethrough. The annular member 142 defines acircumferentially arranged bores 142 a, and a peripheral portion of eachpetal 144 defines bores (not shown) in alignment with the respectivebores of 142 a of the annular member 142 to receive the respective pins182 of the first member of the retainer frame assembly 180, as will bediscussed below.

The guard assembly 140 may be formed from, e.g., a sheet ofplastic/polymeric material, by stamping with a tool that forms thepetals 144. The petals 144 are configured to flex distally (i.e., awayfrom the first member 181 of the retainer frame assembly 180), uponengagement with the surgical instrument 10 to facilitate passage of thesurgical instrument 10 through the seal assembly 150, which, in turn,stretches the seal assembly 150 to increase the size of a centralopening 151 of the seal assembly 150. The increased size of the centralopening 151 of the seal assembly 150 permits receipt of the surgicalinstrument 10 (FIG. 7) through the valve assembly 120.

It is envisioned that the guard assembly 140 may include any number ofpetals 144 and the petals 144 may include flap portions of any size orconfiguration. For a detailed description of a guard assembly, referencemay be made to U.S. Pat. Nos. 5,895,377 and 6,569,120, and InternationalPatent Publication No. WO 91/12838, the entire disclosures of which areall hereby incorporated by reference herein, for exemplary guardassemblies.

With continued reference to FIG. 6, the seal assembly 150 of the valveassembly 120 is configured to provide a seal around an outer surface ofthe surgical instrument 10 passing through the instrument valve housing110. The seal assembly 150 includes a plurality of seal segments 152that are stackable to form a seal having a virtual inner circumferentialsurface defining the central opening 151 to facilitate sealed passage ofthe surgical instrument 10 through the seal assembly 150. Inembodiments, the central opening 151 may be between about 0.025″ andabout 0.100″ in diameter.

The seal assembly 150 may defines, e.g., a substantially planar,hexagonal member. The hexagonal shape facilitates assembly of the sealassembly 150, allowing for quick placement of the seal segments 152 inrelation to each other, and/or by allowing for a quick visual check ofthe seal assembly 150 to ensure that the seal segments 152 are properlyassembled. By forming the central opening 151 out of multiple sealsegments 152, i.e., forming a virtual inner circumferential surface,instead of having a continuous solid opening through a single sealmember, the likelihood of the seal assembly 150 tearing duringinsertion, removal, and/or use of a surgical instrument 10 therethroughis greatly reduced. The seal segments 152 of the seal assembly 150 maybe formed of an elastic material, e.g., rubber, polyisoprene, orsilicone elastomers. In one embodiment, the seal assembly 150 is formedof liquid silicon rubber (LSR). In embodiments, the seal segments 152may include one or more fabric layers. Each seal segment 152 of the sealassembly 150 may be substantially wing-shaped and configured topartially overlap an adjacent seal segment 152 when the seal assembly150 is in the assembled or stacked configuration. Each seal segment 152includes a base portion 152 a and a seal portion 152 b extending fromthe base portion 152 a. The base portion 152 a and the seal portion 152b may be formed of the same or different material. The base portion 152a of the seal segment 152 defines a plurality of openings 153 tofacilitate assembly and retention of the seal assembly 150 in thestacked configuration. More particularly, the plurality of openings 153are configured to receive pins 182 of the first member of the retainerframe assembly 180, for securing the seal segments 152 relative to eachother. In particular, the seal portion 152 b of each seal segment 152 ofthe seal assembly 150 may taper radially inwardly to facilitatereception of the surgical instrument 10 through the seal assembly 150,and/or may enhance sealing about the surgical instrument 10.

In the assembled or stacked configuration, the seal assembly 150includes a substantially planar body having a substantially uniformthickness. It is envisioned that the aspects of the present disclosuremay be modified for use with an access assembly having a substantiallyconical body. Misalignment of any one of the seal segments of the sealassembly 150 may compromise the integrity of the seal assembly 150. Theconfiguration of the seal assembly 150 permits visual inspection of theseal assembly 150 to determine if the seal assembly 150 is assembledproperly.

With reference back to FIGS. 4-6, the centering mechanism 160 inaccordance with an embodiment of the present disclosure is configured tobias the valve assembly 120 towards a generally centered position, i.e.,concentrically positioned within the cavity 115 (FIG. 3), of theinstrument valve housing 110. The centering mechanism 160 permits, e.g.,radial, movement of the valve assembly 120 relative to the instrumentvalve housing 110 when the surgical instrument 10 is received throughthe valve assembly 120 and manipulated by a clinician. The centeringmechanism 160 returns the valve assembly 120 to a generally centeredposition once the surgical instrument 10 is withdrawn from theinstrument valve housing 110 or the radial movement ceases. Thecentering mechanism 160 is configured to engage various points of theinstrument valve housing 110 to bias the centering mechanism 160 to agenerally centered position.

Dynamic leaks are common when a clinician manipulates, e.g., a 5 mmsurgical instrument through a 15 mm port during bariatric procedures. Inorder to reduce and inhibit such dynamic leaks, the centering mechanism160 is compressible when the valve assembly 120 is diametricallydisplaced within the cavity 115 (FIG. 3) of the instrument valve housing110, and the centering mechanism 160 is also resilient such that whenthe surgical instrument 10 is removed from the instrument valve housing110 the centering mechanism 160 returns the valve assembly 120 back tothe generally centered position. In this manner, the centering mechanism160 may reduce occurrence of a dynamic leak during manipulation of thesurgical instrument 10 within the longitudinal passage 111.

The centering mechanism 160 has a substantially flat profile having aplurality of coils 162. The plurality of coils 162 includes an annularbody 164 defining a central opening 166. The central opening 166 isdimensioned to receive the surgical instrument 10 therethrough. Inparticular, the central opening 166 is dimensioned to enable theclinician to manipulate the surgical instrument 10 while providingmaximum degree of freedom. The plurality of coils 162 defines aplurality of inner coil portions 162 a and outer coil portions 162 b.With particular reference to FIG. 5, adjacent inner coil portions 162 adefine a gap 162 c therebetween. The gap 162 c is dimensioned to atleast partially receive a pin 182 (FIG. 4) of the first member 181 ofthe retainer frame assembly 180. In this manner, each inner coil portion162 a is supported by an adjacent pair of pins 182 of the first member181 of the retainer frame assembly 180. The outer coil portion 162 b isradially outward from the seal assembly 150 and is configured to engagethe lateral surface 110 a (FIG. 3) of the instrument valve housing 110.The adjacent pair of pins 182 inhibits inward radial displacement of thecorresponding inner coil portion 162 a, while enabling radialcompression of the outer coil portion 162 b. In this manner, thecentering mechanism 160 is compressible and resilient to bias theoff-centered valve assembly 120 towards a generally centered positionwithin the cavity 115 (FIG. 3) of the instrument valve housing 110.Under such a configuration, once the surgical instrument 10 is withdrawnfrom the valve assembly 120 that is in an off-centered position, thecentering mechanism 160 returns the valve assembly 120 to the generallycentered position. The centering mechanism has the advantage ofomnidirectional, generally constant centering forces being applied tothe seal assembly. The design allows for a mechanism that always ornearly always returns the seal assembly to a central position, as thecentering mechanism is always centered in its natural state. Thecentering mechanism can be made from surgically acceptable metals orappropriate plastics. It can also be made from materials that can bere-sterilized for use in a reusable trocar cannula assembly.

With brief reference back to FIG. 6, the retainer frame member 180 ofthe valve assembly 120 is configured to couple the guard assembly 140,the flange seal member 130, the seal assembly 150, and the centeringmechanism 160 together as a single construct to form the valve assembly120. The retainer frame member 180 includes the first member 181 and asecond member 185. The first member 181 includes a plurality of pins 182extending from a distal surface of the first member 181. The secondmember 185 defines an annular groove 185 a configured to receive theplurality of the pins 182 of the first member 181 to secure first member181 thereto. For example, the pins 182 may be frictionally received inthe annular groove 189 a. Alternatively, the pins 182 may be welded,glued, adhered, bonded or otherwise secured to the annular groove 185 aof the second member 185 in order to secure the first and second members181, 185 together.

The plurality of pins 182 of the first member 181 extends through therespective bores 142 a of the guard assembly 140 and the bores 132 b ofthe flange seal member 130. The plurality of pins 182 further extendsthrough the plurality of openings 153 of the seal assembly 150 and intothe annular groove 185 a of the second member 185. Under such aconfiguration, the guard assembly 140 is received in the recess 135 ofthe flange seal member 130, and the seal assembly 150 is interposedbetween the flange seal member 130 and the second member 185 of theretainer frame assembly 180.

With particular reference back to FIGS. 4 and 5, as discussedhereinabove, each pin 182 of the first member 181 is disposed at leastpartially within the gap 162 c defined by a pair of adjacent inner coilportions 162 a of the centering mechanism 160. Under such aconfiguration, each inner coil portion 162 a is supported by a pair ofadjacent pins 182. In addition, the plurality of pins 182 is received inthe annular groove 185 a of the second member 185. In this manner,portions of the inner coil portions 162 are secured between the sealassembly 150 and the second member 185 of the retainer frame assembly180. In order to further enhance securement of the inner coil portion162 a between the seal assembly 150 and the second member 185, the sealassembly 150 may include radial protrusions 155 peripherally arrangedabout the central opening 151 to support portions of the inner coilportion 162 a of the centering mechanism 160. The outer coil portions162 engage the lateral surface 110 a (FIG. 3) of the instrument valvehousing 110 and biases the valve assembly 120 towards a generallycentered position in the cavity 115 of the instrument valve housing 110.

With reference to FIGS. 6-8, in use, the valve assembly 120 is initiallypositioned generally centered in the instrument valve housing 110 in theabsence of the surgical instrument 10. The outer coil portions 162 b ofthe centering mechanism 160 engage the lateral surface 110 a of theinstrument valve housing 110. At this time, the arcuate portion 134 ofthe flange seal member 130 engages the distal surface of the instrumentvalve housing 110 in a sealing relation. As the surgical instrument 10is introduced into the instrument valve housing 110 through thelongitudinal passage 111 (FIG. 2) of the instrument valve housing 110,the distal end of the surgical instrument 10 engages the petals 144 ofthe guard assembly 140 causing the respective petals 144 to flexdistally towards the seal assembly 150. Such flexing of the petals 144causes the central opening 151 of the seal assembly 150 to open toaccommodate passage of the surgical instrument 10. In this manner, theguard assembly 140 protects the seal assembly 150 from tearing or otherdamage as the surgical instrument 10 is received through and withdrawnfrom the seal assembly 150.

When the surgical instrument 10 is disposed within the longitudinalpassage 111 without any radial forces applied to the surgical instrument10, the valve assembly 120 may be disposed in a generally centeredposition as shown in FIG. 7. However, the valve assembly 120 may movewithin the cavity 115 during a surgical procedure. The clinician maymanipulate the surgical instrument 10 such that the valve assembly 120may be radially displaced, which, in turn, causes some of the outer coilportions 162 b of the centering mechanism 160 to be compressed (FIG. 8).At this time, the arcuate portion 134 (FIG. 6) of the flange seal member130 may engage the lateral surface 110 a (FIG. 3), as well as the distalsurface, of the instrument valve housing 110 in a sealing relation. Oncethe surgical instrument 10 is withdrawn from the instrument valvehousing 110, the centering mechanism 160 returns the valve assembly 120to a generally centered position (FIG. 7), while the arcuate portion 134maintains sealing relation with the distal surface 112 a of the upperhousing section 112.

It is envisioned that the centering mechanism 160 may include coilshaving different shapes and configurations. With reference to FIGS. 9and 10, a centering mechanism 260 may include a plurality of coils 262circumferentially arranged about the centering mechanism 260. Inparticular, each coil 262 may have a circular profile such that a singlecircular coil extends between the lateral surface 110 a and a gapdefined by a pair of adjacent pins 182. As discussed hereinabove, eachcircular coil 262 may be compressed to, e.g., an oblong shape, duringmanipulation of the surgical instrument 10 by the clinician, and mayspring back to the circular shape when the valve assembly 120 returns tothe generally centered position.

With reference now to FIGS. 11 and 12, a centering mechanism inaccordance with another embodiment of the present disclosure isgenerally shown as a centering mechanism 360. The centering mechanism360 is configured for use with the valve assembly 120 (FIG. 6). Portionsof the centering mechanism 360 substantially identical to the centeringmechanisms 160, 260 will not be described herein to avoid obscuring thepresent disclosure in unnecessary detail. The centering mechanism 360may have, e.g., a toroidal or donut shape, including a mesh or aplurality of coils 362. In particular, the centering mechanism 360 isdimensioned to be in the cavity 115 of the instrument valve housing 110.The centering mechanism 360 is disposed distal of the arcuate portion134 (FIG. 6) of the flange seal member 130. Moreover, the centeringmechanism 360 is configured to engage the lateral surface 110 a of theinstrument valve housing 110 when the valve assembly 320 is in agenerally centered position. Under such a configuration, when the valveassembly 320 is radially displaced, portions of the centering mechanism360 are compressed during manipulation of a surgical instrumentextending through the valve assembly 320. At this time, the arcuateportion 134 of the of the flange seal member 130 may engage the lateralsurface 110 a of the instrument valve housing 110 in a sealing relation.With reference to FIG. 13, the centering mechanism 360 defines a centralopening 366 dimensioned to receive the second member 185 of the retainerframe assembly 180 such that the centering mechanism 360 is interposedbetween the lateral surface 110 a and the second member 185 in anuncompressed state, i.e., when the valve assembly 320 is in a normallybiased or a generally centered position.

With reference to FIGS. 14 and 15, the valve assembly 320 may beradially displaced from a normally biased or a generally centeredposition such that portions of the centering mechanism 360 arecompressed against the lateral wall 110 a of the instrument valvehousing 110 and portions of the centering mechanism 360 diametricallyopposing the compressed portions are disengaged from the lateral wall110 a, as shown in FIG. 15. In the absence of any radial force appliedto the surgical instrument, the valve assembly 320 returns to thegenerally centered position. The use of the centering mechanism 360 issubstantially identical to the use of the centering mechanism 160, andthus will not be described herein.

While various embodiments of the present disclosure have been shown anddescribed herein, it will be obvious to those skilled in the art thatthese embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the present disclosure. Accordingly,it is intended that the invention be limited only by the spirit andscope of the appended claims.

What is claimed is:
 1. An access assembly comprising: an instrumentvalve housing defining a cavity; and a valve assembly disposed withinthe cavity of the instrument valve housing, the valve assemblyincluding: a flange seal member including an arcuate portion configuredto adjustably engage a lateral surface of the instrument valve housingin a sealing relation; a seal assembly configured to engage a surgicalinstrument inserted into the access assembly in a sealing relation; acentering mechanism configured to bias the valve assembly towards agenerally centered position within the cavity of the instrument valvehousing, the centering mechanism including a plurality of coils arrangedin a circular configuration and defining a central opening, theplurality of coils including inner coil portions operatively securedwith the seal assembly, and outer coil portions configured to engage thelateral surface of the instrument valve housing; and a retainer frameassembly configured to couple the centering mechanism, the flange sealmember, and the seal assembly as a single construct, the retainer frameassembly including first and second members, the inner coil portions ofthe centering mechanism being disposed between the seal assembly and thesecond member of the retainer frame assembly.
 2. The access assemblyaccording to claim 1, wherein the centering mechanism has asubstantially flat profile.
 3. The access assembly according to claim 1,wherein the centering mechanism is formed of a resilient material totransition the centering mechanism between a first state, in which, thecentral opening of the centering mechanism is disposed in a generallycentered position, and a second state, in which, the central opening isradially displaced from the generally centered position.
 4. The accessassembly according to claim 3, wherein portions of the centeringmechanism are compressible when the centering mechanism is in the secondstate.
 5. The access assembly according to claim 1, wherein each coil ofthe plurality of coils of the centering mechanism has a circularprofile.
 6. The access assembly according to claim 5, wherein a gap isdefined between adjacent pins of the first member of the retainer frameassembly and at least one coil of the plurality of coils extends betweenthe lateral surface of the instrument valve housing and the gap.
 7. Theaccess assembly according to claim 1, wherein adjacent inner coilportions define a gap therebetween.
 8. The access assembly according toclaim 7, wherein the first member of the retainer frame assemblyincludes a plurality of pins and the second member of the retainer frameassembly defines an annular groove configured to receive the pluralityof pins.
 9. The access assembly according to claim 8, wherein each pinof the plurality of pins of the first member is at least partiallydisposed in the gap defined between the adjacent inner coil portionssuch that at least a portion of each inner coil portion is securedbetween adjacent pins.
 10. The access assembly according to claim 8,wherein the outer coil portions of the centering mechanism are disposedradially outward of the second member of the retainer frame assembly.11. The access assembly according to claim 1, wherein the seal assemblyincludes a plurality of radial protrusions peripherally arranged about acentral opening of the seal assembly, each radial protrusion of theplurality of radial protrusions configured to support a correspondinginner coil portion of the centering mechanism.
 12. The access assemblyaccording to claim 1, wherein the valve assembly further includes aguard assembly configured to be secured with the flange seal member, theguard assembly configured to protect the seal assembly during insertionand manipulation of the surgical instrument.
 13. The access assemblyaccording to claim 12, wherein the flange seal member includes opposingfirst and second surfaces, the guard assembly disposed on the firstsurface of the flange seal member in a superposed relation and the sealassembly detachably secured with the second surface of the flange sealmember.
 14. An access assembly comprising: an instrument valve housingdefining a cavity; and a valve assembly disposed within the cavity ofthe instrument valve housing, the valve assembly including: a flangeseal member including an arcuate portion configured to adjustably engagea lateral surface of the instrument valve housing in a sealing relation;a seal assembly configured to engage a surgical instrument inserted intothe access assembly in a sealing relation; a centering mechanismconfigured to bias the valve assembly towards a generally centeredposition within the cavity of the instrument valve housing, thecentering mechanism including a mesh having a toroidal shape, the meshconfigured to be interposed between the lateral surface of theinstrument valve housing and the flange seal member.
 15. The accessassembly according to claim 14, wherein the mesh is disposed distally ofthe arcuate portion of the flange seal member.
 16. The access assemblyaccording to claim 14, wherein the mesh defines a central opening and istransitionable between a first state, in which, the central opening ofthe mesh is in a generally centered position, and a second state, inwhich, the central opening of the mesh is radially displaced.
 17. Theaccess assembly according to claim 15, wherein the valve assemblyincludes a retainer frame assembly including first and second members,the retainer frame assembly configured to couple the flange mechanism,the flange seal member, and the seal assembly as a single construct. 18.The access assembly according to claim 16, wherein the central openingof the mesh is concentrically disposed with a central opening defined bythe seal assembly.
 19. The access assembly according to claim 15,wherein a portion of the arcuate portion of the flange seal member is insuperposed relation with the mesh.
 20. The access assembly according toclaim 15, wherein the mesh is radially compressible such that a portionof the arcuate portion of the flange seal member engages the lateralsurface of the instrument valve housing when at least a portion of themesh is compressed.